一、动态添加或移除工作流活动
首先添加一个顺序的空白工作流。
然后添加一个Winform程序，界面如下：
代码如下：
namespace WinForm { public partial class Form1 : Form { private WorkflowRuntime workflowRuntime = null; private WorkflowInstance workflowInstance = null; private WorkflowChanges wfchange = null; public Form1() { InitializeComponent(); workflowRuntime = new WorkflowRuntime(); workflowRuntime.StartRuntime(); } private void button1_Click(object sender, EventArgs e) { Type type = typeof(WorkflowConsoleApplication1.Workflow1); workflowInstance = workflowRuntime.CreateWorkflow(type); Activity Act = workflowInstance.GetWorkflowDefinition(); wfchange = new WorkflowChanges(Act); CodeActivity code1 = new CodeActivity("codeactivity1"); code1.ExecuteCode += delegate(object s, EventArgs ea) { MessageBox.Show("工作流被调用!"); }; wfchange.TransientWorkflow.Activities.Insert(0, code1); } private void button2_Click(object sender, EventArgs e) { workflowInstance.ApplyWorkflowChanges(wfchange); workflowInstance.Start(); } } }
效果如下：
二、动态添加或移除容器活动
向工作流的容器类型复合活动中动态添加一个子活动。
添加一个Sequence容器，然后通过代码向其内部动态添加一个Code类型的子活动。
添加一个Winform程序，界面不变：
namespace WinForm { public partial class Form1 : Form { private WorkflowRuntime workflowRuntime = null; private WorkflowInstance workflowInstance = null; private WorkflowChanges wfchange = null; public Form1() { InitializeComponent(); workflowRuntime = new WorkflowRuntime(); workflowRuntime.StartRuntime(); } //添加一个工作流 private void button1_Click(object sender, EventArgs e) { Type type = typeof(WorkflowConsoleApplication1.Workflow1); workflowInstance = workflowRuntime.CreateWorkflow(type); Activity Act = workflowInstance.GetWorkflowDefinition(); wfchange = new WorkflowChanges(Act); //创建一个Code活动 CodeActivity code1 = new CodeActivity("codeactivity1"); code1.ExecuteCode += delegate(object s, EventArgs ea) { MessageBox.Show("sequenceActivity里的Code工作流被调用!"); }; //添加工作流到容器中 SequenceActivity seq = (SequenceActivity)wfchange.TransientWorkflow.Activities["sequenceActivity1"]; seq.Activities.Add(code1); } //移除一个工作流 private void button3_Click(object sender, EventArgs e) { Activity Code1 = wfchange.TransientWorkflow.Activities["codeactivity1"]; SequenceActivity seq = (SequenceActivity)wfchange.TransientWorkflow.Activities["sequenceActivity1"]; seq.Activities.RemoveAt(0); } //执行 private void button2_Click(object sender, EventArgs e) { workflowInstance.ApplyWorkflowChanges(wfchange); workflowInstance.Start(); } } }
改动的部分就是红色部分代码，添加删除一个活动一样是Add、Remove。
三、动态修改判断条件
在WWF提供的各种活动空间中，像IfElse和While这两种基于规则模式的活动是需要设置其逻辑判断条件的。该判断条件分为两种类型，一种是"Code Condition"，利用程序代码来定义其逻辑的判断条件，另外一种是"Declarative Rule Condition"。
首先建立一个顺序类型的工作流项目，然后添加一个IfElse活动到该工作流设计界面，将IfElse活动空间的两条分支分别命名为"IfBranch"和"ElseBranch"。每条分支添加一个Code活动控件。工作流界面如下：
将默认的判断条件设置为如下：
工作流代码如下：
public sealed partial class Workflow1 : SequentialWorkflowActivity { public int condition; public int Condition { get { return condition; } set { condition = value; } } public Workflow1() { InitializeComponent(); } private void Code1(object sender, EventArgs e) { MessageBox.Show("If分支被执行!"); } private void Code2(object sender, EventArgs e) { MessageBox.Show("Else分支被执行!"); } }
创建一个Winform程序，界面如下：
代码如下：
namespace WinForm { public partial class Form1 : Form { private WorkflowRuntime workflowruntime; private WorkflowInstance workflowinstance; public Form1() { InitializeComponent(); workflowruntime = new WorkflowRuntime(); workflowruntime.StartRuntime(); } //添加一个工作流 private void button1_Click(object sender, EventArgs e) { Dictionary<string, object> parameters = new Dictionary<string, object>(); parameters.Add("Condition", Convert.ToInt32(this.textBox2.Text)); Type wftype = typeof(WorkflowConsoleApplication1.Workflow1); workflowinstance = workflowruntime.CreateWorkflow(wftype, parameters); //WWF对所有运行中的工作流都可以通过"WorkflowChanges"对象来实现修改 //GetWorkflowDefinition得到工作流活动的集合 WorkflowChanges workflowchanges = new WorkflowChanges(workflowinstance.GetWorkflowDefinition()); //将工作流所有的活动进行克隆，克隆出来的对象保存在comactivity中 CompositeActivity comactivity = workflowchanges.TransientWorkflow; //RunleDefinitions类专门用于对".rules"文件进行操作 RuleDefinitions ruleDefinitions = (RuleDefinitions)comactivity.GetValue(RuleDefinitions.RuleDefinitionsProperty); //获取所有的逻辑判断集合 RuleConditionCollection conditions = ruleDefinitions.Conditions; //从Condition对象中获取具体的"Condition1"逻辑判断的信息，"Condition1"以"Declarative Rule Condition"方式定义判断条件的名称 RuleExpressionCondition condition1 = (RuleExpressionCondition)conditions["Condition1"]; //对原工作流的condition1逻辑判断条件进行修改 (condition1.Expression as CodeBinaryOperatorExpression).Right = new CodePrimitiveExpression(Convert.ToInt32(this.textBox1.Text)); //将修改后的信息应用回工作流实例 workflowinstance.ApplyWorkflowChanges(workflowchanges); //重新启动工作流 workflowinstance.Start(); } } }
运行效果如下：
留意到判断条件已经完全改为为Winform中的判断条件。
四、动态添加StateActivity活动
在状态机工作流中同样可以动态加载或修改原有的业务流程。
首先定义一个接口如下：
[ExternalDataExchange] public interface IClass { //入党申请 event EventHandler<ExternalDataEventArgs> AdmittedIntoParty; //介绍人意见 event EventHandler<ExternalDataEventArgs> SponsorCommit; //党委会审批 event EventHandler<ExternalDataEventArgs> PCApproved; }
新建一个状态机工作流如下：
前两个EventDriven里面添加两个HandleExternalEvent，并绑定刚刚定义的接口里的事件。
新建一个Winform程序如下：
从上至下分别是button1、2、3、4。
代码如下：
namespace WinForm { public partial class Form1 : Form, ClassLibrary1.IClass { private WorkflowRuntime workflowruntime; private WorkflowInstance workflowinstance; private ExternalDataExchangeService exterserv; public event EventHandler<ExternalDataEventArgs> AdmittedIntoParty; public event EventHandler<ExternalDataEventArgs> SponsorCommit; public event EventHandler<ExternalDataEventArgs> PCApproved; public Form1() { InitializeComponent(); workflowruntime = new WorkflowRuntime(); exterserv = new ExternalDataExchangeService(); workflowruntime.AddService(exterserv); exterserv.AddService(this); workflowruntime.StartRuntime(); Type wftype = typeof(WorkflowConsoleApplication1.Workflow1); workflowinstance = workflowruntime.CreateWorkflow(wftype); workflowinstance.Start(); } private void Form1_Load(object sender, EventArgs e) { SetStateComboBox(); } private void SetStateComboBox() { comboBox1.Items.Clear(); StateMachineWorkflowInstance StateMachineInstance = new StateMachineWorkflowInstance(workflowruntime, workflowinstance.InstanceId); ReadOnlyCollection<StateActivity> states = StateMachineInstance.States; foreach (StateActivity allState in states) { this.comboBox1.Items.Add(allState.Name); } } private void button1_Click(object sender, EventArgs e) { AdmittedIntoParty(null, new ExternalDataEventArgs(workflowinstance.InstanceId)); this.button1.Enabled = false; } private void button2_Click(object sender, EventArgs e) { Activity root = workflowinstance.GetWorkflowDefinition(); WorkflowChanges changes = new WorkflowChanges(root); //创建一个状态活动 StateActivity sponsorsubmit = new StateActivity(); sponsorsubmit.Name = "介绍人提交意见"; //创建一个EventDrivenActivity EventDrivenActivity sponsoreven = new EventDrivenActivity(); sponsoreven.Name = "SponsorEvent"; //向状态活动中添加EventDrivenActivity sponsorsubmit.Activities.Add(sponsoreven); //创建一个HandleExternalEventActivity HandleExternalEventActivity sponsorHandle = new HandleExternalEventActivity(); sponsorHandle.Name = "SponsorHandle"; sponsorHandle.InterfaceType = typeof(ClassLibrary1.IClass); sponsorHandle.EventName = "SponsorCommit"; //sponsorHandle.Invoked +=new EventHandler<ExternalDataEventArgs>(sponsorHandle_Invoked); //向EventDrivenActivity中添加HandleExternalEventActivity活动 sponsoreven.Activities.Add(sponsorHandle); //向EventDrivenActivity中添加SetStateActivity活动 SetStateActivity setSponsorapproved = new SetStateActivity(); //由于工作流是默认命名，所以1和2都已经存在 setSponsorapproved.Name = "setStateActivity3"; setSponsorapproved.TargetStateName = "党委会审批"; sponsoreven.Activities.Add(setSponsorapproved); //将状态活动添加进WorkflowChanges changes.TransientWorkflow.Activities.Add(sponsorsubmit); //将动态加载的活动更新至工作流 workflowinstance.ApplyWorkflowChanges(changes); SetStateComboBox(); this.button2.Enabled = false; } private void button3_Click(object sender, EventArgs e) { StateMachineWorkflowInstance stateInstance = new StateMachineWorkflowInstance(workflowruntime, workflowinstance.InstanceId); stateInstance.SetState("介绍人提交意见"); SponsorCommit(null, new ExternalDataEventArgs(workflowinstance.InstanceId)); this.button3.Enabled = false; this.button2.Enabled = false; } private void button4_Click(object sender, EventArgs e) { PCApproved(null, new ExternalDataEventArgs(workflowinstance.InstanceId)); this.button1.Enabled = false; this.button2.Enabled = false; this.button4.Enabled = false; } } }
显示结果如下：
当点击添加介绍人意见后，整个状态机工作流会在党委审批前，增加一个状态State，介绍人是否已提交意见。
1、取得工作流定义的对象，然后将它作为"WorkflowChanges"对象保存。
2、创建一个State对象，并设置其Name为"介绍人提交意见"。
3、往State内部添加一个EventDriven。
4、往EventDriven里面添加一个HandleExternalEvent子活动。并与接口中定义的事件进行绑定。
5、通过SetStateActivity活动的TargetStateName设置状态间的迁移关系，注意SetStateActivity活动也是EventDriven的子活动，也应该将它添加到EventDriven当中去。
6、将改动应用回工作流。
